Three Letter String

NET

network
nettle
bonnet
dragnet
rinnet

FIN

FIN

affinity
finish
griffin
finicky
surfing

BRE

BRE

brevity
abbreviate
cornbread
heartbreak
breezy

CRO

CRO

acronym
crony
crossword
Croatia
crock

LUR

LUR

lure
lurid
alluring
blurb
lurk

REB

REB

rebellion
rebirth
Zagreb
barebones
rebus

BUS

BUS

business
bust
rubus
filibuster
combustion

KMA

KMA

K-Mart
bookmark
workman
Walkman
milkman

LTY

LTY

faulty
penalty
salty
guilty
silty

:thud

SWE

SWE

sweet
sweat
sweater
bittersweet
windswept

ALE